CA1297510C - Gripper-device for a printing machine - Google Patents
Gripper-device for a printing machineInfo
- Publication number
- CA1297510C CA1297510C CA000553029A CA553029A CA1297510C CA 1297510 C CA1297510 C CA 1297510C CA 000553029 A CA000553029 A CA 000553029A CA 553029 A CA553029 A CA 553029A CA 1297510 C CA1297510 C CA 1297510C
- Authority
- CA
- Canada
- Prior art keywords
- gripper
- shaft
- finger
- resilient
- spring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000007935 neutral effect Effects 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 9
- 230000006835 compression Effects 0.000 claims description 5
- 238000007906 compression Methods 0.000 claims description 5
- 239000000835 fiber Substances 0.000 claims 4
- 229920002430 Fibre-reinforced plastic Polymers 0.000 claims 1
- 150000001875 compounds Chemical class 0.000 claims 1
- 238000010276 construction Methods 0.000 claims 1
- 239000011151 fibre-reinforced plastic Substances 0.000 claims 1
- 230000005484 gravity Effects 0.000 claims 1
- 238000006073 displacement reaction Methods 0.000 abstract description 8
- 230000036316 preload Effects 0.000 description 6
- 238000005452 bending Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000639 Spring steel Inorganic materials 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H5/00—Feeding articles separated from piles; Feeding articles to machines
- B65H5/08—Feeding articles separated from piles; Feeding articles to machines by grippers, e.g. suction grippers
- B65H5/14—Details of grippers; Actuating-mechanisms therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41F—PRINTING MACHINES OR PRESSES
- B41F21/00—Devices for conveying sheets through printing apparatus or machines
- B41F21/04—Grippers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41F—PRINTING MACHINES OR PRESSES
- B41F21/00—Devices for conveying sheets through printing apparatus or machines
- B41F21/10—Combinations of transfer drums and grippers
- B41F21/104—Gripper details
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)
- Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
- Sheets, Magazines, And Separation Thereof (AREA)
Abstract
ABSTRACT
A gripper-device for a printing machine, comprising a spring gripper-finger connected rigidly to the gripper-shaft, is designed, with the simplest possible configuration, in such a manner that, when the grip is closed, there is practically no displacement of the material to be printed which has been gripped.
To this end, the gripper-device is designed in such a manner that the neutral fibres of the spring-section adjoining the tip of the gripper, when designed as an individual spring-rod, run substantially in the plane defined by the longitudinal axis of the gripper-shaft and by the tip of the gripper, and when designed in the form of spring-rods arranged in parallel with, and spaced from each other, run in parallel with this plane.
A gripper-device for a printing machine, comprising a spring gripper-finger connected rigidly to the gripper-shaft, is designed, with the simplest possible configuration, in such a manner that, when the grip is closed, there is practically no displacement of the material to be printed which has been gripped.
To this end, the gripper-device is designed in such a manner that the neutral fibres of the spring-section adjoining the tip of the gripper, when designed as an individual spring-rod, run substantially in the plane defined by the longitudinal axis of the gripper-shaft and by the tip of the gripper, and when designed in the form of spring-rods arranged in parallel with, and spaced from each other, run in parallel with this plane.
Description
The invention relates to a gripper-device for a printing mach;ne for handling sheet material, with a gripper-shaft adapted to pivot about its longitudinal axis and a gripper-finger comprising a spring-section and being rigidly connected to the gripper-shaft in such a manner that the tip of the gripper, when the gripper-shaft is pivoted in a first direction, is moved away from the gripper-pad and, when the said shaft is p;voted in the opposite direction, the tip of the gripper comes into contact with the said pad, further pivoting of the said shaft in the second direction applying a retaining force to the said pad; and w;th means for adjusting the contact between the tip of the gripper and the gripper-pad.
A gripper-device of this kind is known from EP-OS O 152 553. In this case the gripper-finger is made resilient and is screwed to a divided clamping piece which connects it to the gripper-shaft but secures it against rotation in relation thereto.
When this gripper-device closes, the tip of the gripper-finger initially comes into contact with a gripper-pad. In order to ensure an adequate retaining force in the a-rea, covered by the tip of the gripper, of a printed sheet, the gripper-shaft is rotated further in the direction of closing. In this case, the retaining force is the result of the deflection of the tip of the gripper, associated therewith, from its assumed position in relation to the clamping piece when the gripper-device is in the open condition.
As a result of the contact between the tip of the gripper and the gripper-pad, the circular motion of the tip of the gripper is ~Z975~0 interrupted. Further rotation of the gripper-shaft in the direction of closing causes the gripper-finger to behave like a connecting rod wh;ch is resilient in the direction of rotation of a crank-drive, is clamped firmly to the crankshaft, and is guided in a cross-head. As a result of this, the tip of the gripper moves in relation to the gripper-pad and thus interferes with the keeping of the register of a clamped printed sheet.
A gripper-device known from EP-PS 0 073 955 uses the analogy between a gripper-device of this kind and a crank-drive to restrict this displacement of the tip of the gripper to the shortest path. It makes use, to this end, of a bent, resilient gripper-finger, the resilient end of which, facing the gripper shaft, and the tip of which, lie upon a common straight line passing through the middle of the gripper-shaft. In this connection, a Z-shaped configuration of the gripper-finger causes the straight section thereof to behave approximately like the arms of a multiple articulated lever hinged to the gripper-shaft in the clamped position of the gripper-finger. As a result of changes in the angular position of the arms of the lever, restoring forces act upon these arms, and the end corresponding to the tip of the gripper bears frictionally upon the gripper-pad under the retaining force of the gripper-finger. The increase in the distance between the gripper-pad and the clamped end of the gripper finger, associated with rotation of the gripper-shaft by the stated amount in order to provide the said retaining force, is intended to produce, in this known device, upon deflection of the gripper-finger in its longitudinal direction, an automatic corresponding increase in the effective length of the gripper-finger. This is intended to prevent displacement of the tip of the gripper on the gripper-pad.
Actually, however, the desired effect is not achieved with the means disclosed. Instead, as a result of its Z-shaped design, the gripper-finger is very flexible in the direction passing through the middle of the gripper-shaft and through the tip of the gripper. As a result of this, the tip of the gripper shifts when the gripper closes or in the event of tensile forces from the paper. This effect cannot be eliminated with the known gripper without additional measures.
Another attempt to prevent the said displacement of the tip of the gripper on the gripper-pad is known from the device according to US Patent 2 906 204.
This is intermediate between a gripper-finger secured to the gripper-shaft and a gripper-part adapted to pivot about the gripper-shaft and acted upon by a closing spring, as may be gathered from US Patent 3 536 321.
The device according to US Patent 2 906 204 is intended to prevent the said displacement by means of a floating gripper-finger. The rear part of this engages around about half the circumference of the gripper-shaft, but does not bear upon it.
Only the areas thereof adjoining the semicircular part are caused to bear, under the force of a spring, against a half-shell connected to the gripper-shaft but secured against rotation in relation thereto. The area of the gripper-finger remote from the tip, bearing under spring-force against the lower half of the shell, is also held, by means of a bore in the gripper-finger at right angles to the supporting surface of the gripper-finger on the half-shell and a bolt alignment therewith, for the purpose of lZ~7S~O
clamping the lower and upper half-shells, in such a manner that the gripper-finger, after leaving the opposing supporting area, can tilt in relation to the bolt.
As a whole, this known device constitutes a so-called hook-gripper with which additional rotation of the gripper-shaft by the stated amount is to be used to obtain an adequate retaining force by resilient support of the gripper-finger. Here again - as in the case of the Z-shaped design - the gripper, when loaded in its longitudinal direction through the middle of the gripper-shaft and defined by the tip of the gripper, is not resistant to bending. Instead, the material carried around the gripper-shaft permits the gripper to deflect in the longitudinal direction and leads to displacement upon the paper.
Furthermore, floating mounting of the gripper-finger does not ensure reproducible grasping and holding of a printed ! sheet at one and the same location. Play-free mounting of the gripper-finger, however, is an important prerequisite in obtaining register-keeping pressure.
A gripper-finger, the spring-section of which consists of two spring-rods arranged in parallel with, and spaced from, each other, is known per se from US Patent 3,536,321.
In this case, however, a stack of springs is secured rigidly to a first ring adapted to rotate freely upon the gripper-shaft. In the one direction of rotation, this ring is carried along by a second ring secured to the gripper shaft while, in the other direction of rotation, it is rotated against a stop by the action of a tension-spring. Arranged at the top end of the gripper-finger is a guide-rod passing through a platform of the loose ring. Under the action of a compression-spring bearing against this platform, the said guide-rod urges the top end in the direction of closing. It is pressed in the opposite direction by the second ring connected to the gripper-shaft but secured against rotation in relation thereto.
Moreoever, the arrangement as a whole is such that the spring-rods are substantially relieved upon contact with the gripper-pad, and the retaining force is applied by the compression spring clamped between the end of the guide-rod and the platform.
The spring-rods thus assume the function of approximately parallel guidance of the tip of the gripper in the end-phase of the closing movement.
For the purpose of adjusting the contact between the tip of the gripper and the gripper-pad, a foot adjustable along the guide-rod is provided, against which the other end of the compression-spring, one end of which bears against the said platform, bears.
This gripper-device naturally has a certain amount of play in the mounting of the gripper-finger on the gripper-shaft.
The mass-inertia forces are varied during rotation in each direction by tightening or loosening the loose ring of the driver.
Co-operation with the springs activated thereby also causes unwanted torsional vibration in the gripper-device as a whole. It is the purpose of the present invention to design a gripper-device of the type mentioned at the beginning hereof in such a manner ~Z9751~
that, even with the simplest possible design of gripper-finger, displacement of the tip of the gripper on the gripper-pad is almost zero.
According to the invention, this purpose is accomplished, with a gripper-device of the type mentioned at the beginning hereof, in that the neutral fibres of the spring-section adjoining the tip of the gripper, when designed as an individual spring-rod, run substantially in the plane defined by the longitudinal axis of the gripper-shaft and by the tip of the gripper, and when designed in the form of spring-rods arranged in parallel with, and spaced from, each other, run in planes parallel with this plane.
The object of the invention opens up the possibility, especially when using only one spring-rod, of providing a device with a relatively small mass moment of inertia which may be used with advantage in high-speed printing machines.
The configurations of the object of the invention may be easily assembled and disassembled, with no need to remove the gripper-shaft from the machine.
Furthermore, the adjusting means provide accurate individual adjustment of the contact between the tip of the gripper and the printed sheet clamped between it and the gripper-pad, so that production tolerances and, if so desired, differences in the thickness of the paper may easily be compensated for.
In contrast to the floating gripper-finger known from ~Z97~
the cited state of the art, the object of the invention ensures reproducible placement of the tip of the gripper upon a spPcific contact location in relation to the printed sheet, so that the latter is not subjec~ed to changes arising from differences in gripper action.
All of this requires only a relatively small number of very simple and light components, so that precise functioning may abe acnieved inexpensively.
The object of the invention is particularly suitable for incorporation into a printing machine in such a manner that the middle of the gripper-shaft is located externally of the imaginary extension of the sheet material clamped by the gripper-device beyond the front edge thereof.
Special shaping of the gripper-finger, in order to achieve a preload in the installed position, may be dispensed with.
One advantageous configuration of the object of the invention is characterized in that a gripper-finger having a spring-section in the form of a single spring-rod, passes freely through the gripper-shaft, the end thereof remote from the tip of the gripper being clamped to provide a rigid connection to the gripper-shaft.
A gripper-device of this kind may be used with advantage in close quarters, since it permits the use of relatively long and therefore flexible gripper-fingers at short distances between the gripper-shaft and the gripper-pad, thus preventing any ~ 8 -inadmissible bending stresses.
According to another configuration, in the vicinity of the opening remote from the tip of the gripper in a diametral recess through which the gripper-finger passes, the cross-sections of the recess and of the spring-rod match each other over a short length.
This facilitates alignment of the gripper-finger with the gripper-shaft.
According to another configuration, a clamping dev;ce, which connects the gripper-finger rigidly to the gripper-shaft, comprises a cylindrical clamping sleeve clamped between two jaws braced to the gripper-shaft and provided with a central longitudinal slot in which the spring-rod is clamped.
As a result of this, the gripper-finger is rotatable along with its longitudinal axis and may thus be aligned, particularly simple, to bear snugly upon a gripper-pad associated therewith, for which purpose the clamping device need only be loosened slightly.
Another configuration is characterized in that the end of the spring-rod remote from the tip of the gripper comprises a cylindrical extension integral with the spring-rod, the longitudinal axis of the said extension being in alignment with the longitudinal axis of the diametral recess and the said extension being clamped between the jaws braced to the gripper-shaft.
This facilitates still further the assembly of the gripper-device.
According to another configuration, a second section of the spring-rod, adapted to the external contour of the gripper-shaft adjoins the spring-section of the gripper-finger designed as a spring-rod, the said second section bearing upon the gripper-shaft and being clamped between it and a clamping piece comprising adjusting means.
A gripper-device of this kind may be used with advantage whenever space is not a problem.
Another configuration is characterized by a compression-spring arranged in parallel with a gripper-finger designed as a spring-rod, the direction in which fDrce is introduced being at right angles to the neutral fibres, the said compression-spring bearing upon a clamping device comprising adjusting means for connecting the gripper-finger to the gripper-shaft.
This provides particularly satisfactory conditions as regards bending stress when the gripper-finger is in the clamped position.
According to another configuration, gripper-fingers, in which the neutral fibres of the spring-section run in planes parallel with the plane determined by the longitudinal axis of the gripper-shaft and by the tip of the gripper, are formed by a bottom part and a top part, with the spring section connecting the bottom part in the form of two parallel rods are secured with the bottom part directly to the gripper-shaft.
This facilitates assembly still further.
According to another configuration the spring-rods are arranged symmetrically with the gripper-shaft.
~2g7510 This configuration combines the advantage of simplified assembly and the applicability of a gripper-device according to the invention to close quarters, since this means that the spring-rods may be extended beyond the middle of the gripper-shaft.
Another configuration is characterized in that one of the parts of the gripper-finger, connected together by the spring-rods, comprises an abutment of the adjusting means, while the other part comprises an element of the adjusting means bearing upon the said abutment.
According to another configuration, the top part, the bottom part, the abutment and the spring-rods form a one-piece gripper-finger.
In this case the gripper-finger may be produced highly economically from an extruded section.
Another configuration is characterized in that the two spring-rods are formed by the legs of a U-shaped leaf-spring, in that the part of the leaf-spring uniting the two legs is clamped to the non-resilient top part, and in that the ends of the legs are clamped between the gripper-shaft and a clamping shell adapted to the cross-section thereof.
A gripper-device of this kind is particularly suitable for short runs.
According to another configuration, a common clamping shell is provided for both leg-ends.
In the case of a gripper-device particularly suitable ~Zg751~
for short runs, this reduces the number of necessary parts.
Another configuration is characterized in that arranged on the side of the gripper-shaft facing the clamp;ng shell, between the legs of the U-shaped leaf--spring, is an adjusting block adapted to the contour of the gripper-shaft, the said block being clamped to the gripper-shaft jointly with the clamping shell and compris;ng adjusting means adapted to be applied to the upper leg of the leaf-spring.
This provides good accessibility to the attachment means for a gripper-device consisting of a plurality of individual parts.
According to another configuration, the adjusting means provided are such that they may be used to lock the gripper-finger.
Another configuration is characterized in that adjusting means designed to twist the gripper-finger comprise two adjusting screws spaced apart in the longitudinal direction of the gripper-shaft.
Gripper-devices designed according to another configuration make it possible for the gripper-finger, without loosening the clamping means with which it is secured to the gripper shaft, to be set up in such a manner that the tip of the gripper rests flatly upon the gripper-pad associated therewith.
According to another configuration, the gripper finger is of composite design.
This provides for optimal adaptation of the choice of materials to given requirements for the different sections of a gripper-finger according to the invention, for example satisfactory adhesion of the surface of the tip of the gripper and sat;sfactory resiliency of the spring-section of the gripper-finger.
According to another configuration, the components constituting the spring-section are preferably made of a fibre-reinforced synthetic material.
This makes it possible to reduce still further the mass moment of inertia of a gripper-finger according to the invention.
Examples of embodiment and advantageous configurations of the invention are explained hereinafter in greater detail in conjunction with the drawings attached hereto, wherein:
Fig. 1 is a cross section through a gripper-shaft carrying a gripper-finger in the form of a spring rod for an example in which the gripper-finger passes through the gripper-shaft;
Fig. 2 is a cross-section along the line 2 in Fig. l;
Fig. 3 is a corresponding part-section of an example with a gripper-finger rotatable in its clamped position;
Fig. 4 is a corresponding cross-section of an example with a gripper-finger bearing against the gripper-shaft in the form of a spring-rod;
~2g7510 F;g. 5 ;s a correspond;ng cross-section of an example in which the bearing of the gripper-finger upon the gripper-shaft is modified:
Fig. 6 is a cross-section through a gripper-shaft w;th S a gripper-finger consisting of parallel spring-rods mounted thereupon;
Fig. 7 is a corresponding cross-section of an exampl e w;th spr;ng-rods arranged symmetrically with the gripper-shaft, Fig. 8 is a corresponding cross-section through an alternative to Fig. 7, Fig. 9 is a plan view of a gripper device according to F;g. 8.
Figs. 1 and 2 ;llustrate an example of embodiment which is particularly suitable for use in close quarters. In this case, gripper-shaft 15 is provided with a diametral recess 16 the cross-sect;on of which is larger than that of the gripper-f;nger passing through the said recess.
The gripper-finger is in the form of a spring-rod which carries at one end a gripper-tip 3 and is clamped at the other end, externally of opening 21, remote from the tip of the gripper, in recess 16, between two jaws 17, 18 which, in turn, are braced to gripper-shaft 15 by means of two screws 19, 20.
Jaws 17, 18 therefore constitute the rigid connection between gripper-finger 2.2 and gripper-shaft 15.
lZ975~() - 14 ~
The lower jaw (in Fig. 1) also comprises adjusting means in the form of a screw 13 which engages in a threaded hole 14 in the lower jaw and bears against the gripper-finger.
Arranged between the upper surface of gripper-finger 2~2 and upper jaw 17 is a compression-spring 23 which bears upon the spring-rod. The direction of the force of this spring is at right angles to the neutral fibres of resilient section 1.2.
Fig. 1 illustrates the operative condition in which the tip of the gripper comes into contact with gripper-pad 8. In this case, the neutral fibres of the spring-rod lie in plane 60 defined by the longitudinal axis of the gripper-shaft and by the gripper tip. In this position, the gripper-finger is already preloaded by the compression spring and its own preload. These preloads are picked up by adjusting screw 14. In order to achieve an adequate retaining force of the tip of the gripper upon the pad, it therefore needs only an extremely slight deflection of the tip of the gripper in relation to the clamped other end of the spring-rod since, as soon as the spring-rod is lifted off adjusting screw 14, the preload forces act upon the gripper-pad as a result of additional pivoting of the gripper-shaft in the direction of closing.
In order to facilitate rapid and positionally correct assembly of the gripper-device to the gripper-shaft, in the vicinity of mouth 21, remote from the tip of the gripper, of diametral recess 16, the cross-sections of recess 16 and gripper-finger 2.2 match each other over a short length (Fig.2).
1297~1~
In the configuration according to Fig. 3, the end of the spring-rod remote from the tip of the gripper is accomodated in a central slot between upper and lower jaws 17.1, 1~.1 of a clamped sleeve 24. To this end thP said jaws are shaped in such a manner that the left-hand ends thereof (Fig.3) form a cylindrical pick up 25 for similarly cylindrical sleeve 24. Thus by rotating the clamping sleeve and then bracing the two jaws, the spring-rod may be adjusted in such a manner that the tip of the gripper bears uniformly upon the gripper-pad. The said sleeve is provided with flats so that it can be rotated by means of a tool.
According to a configuration not shown in the drawing, spring-rod 2.2 and clamping sleeve 24 (Fig. 3) may also be made in one piece. To this end, the end of the spring-rod remote from the tip of the gripper is provided with a cylindrical extension which fits rotatably in pick-up 25.
In this connection, rapid and positionally correct assembly is achieved in that the diameters of the diametral recess and of the cylindrical extension are adapted to each other, the pick-up, formed with the clamping jaws, for the cylindrical extension, is in alignment with the diametral recess, and the cylindrical extension engages, over a short length, in the said diametral recess.
In order to rotate the cylindrical extension~ and thus the tip of the gripper also, into a position in which the latter lies uniformly upon the gripper-pad, it is again desirable to provide the cylindrical extension with flats for a tool.
Figs. 4 and 5 show gripper-devices according to the invention which m~y be used with advantage in a sheet-transferring lZ9751~) - 16 ~
device or the impression-cylinder of a printing machine. If sufficient room is available, resilient section 1 of gripper-finger 2.2.1 may be made so long that major deflections of tip 3 of the gripper, during the processing cardboard, for example, do not produce inadmissibly high bending stresses at clamping location 4.
The neutral fibres of the spring section of the gripper-finger lie in a position preloaded by the adjusting means in plane ~0 which is defined by the longitudinal axis of gripper-shaft 5,5.1 and tip 3 of the gripper.
Gripper-finger 2,2.1 is in the form of a spring-rod carrying tip 3 at its free end. The gripper-devices (Figs. 4,5) are again shown in the operative condition in which the tip of the gripper is just coming into contact with the gripper-pad. In the examples of embodiment shown, this is a pad 8 secured to a wall 6 of a channel in a cylinder 7.
For the purpose of actuating the gripper-device, gripper-shaft 5 is rotated, in known fashion, through a specific angle in relation to cylinder 7 in one direction and the other.
By corresponding clockwise rotation through a first part of the pivot-angle, the tip of the gripper moves from a position, not shown, corresponding to the open gripper-device, into the position shown in the drawing. Further rotation through the remaining part of the angle presses the tip of the gripper against pad 8 and applies a retaining force, the printed sheet being thus clamped between the tip of the gripper and the gripper-pad.
1Z~7510 - 17 _ At the same time, deflection of the spring section deflects tip 3 of the gripper to a small extent in relation to clamping location 4 in the direction of an arc around the said clamping location.
All that is necessary to produce an adequate retaining force is again a very slight deflection of the tip of the gripper, since the gripper-finger is already preloaded by the adjusting means. In this connection there is practically no displacement of the tip of the gripper on the gripper-pad as a result of this deflection.
Gripper-finger 2,2.1, in the form of a spring-rod (Figs.
4,5), comprises a non-resilient section adjoining spring-section 1, and is clamped between it and the clamping piece. To this end, the said clamping piece is provided with a supporting surface 10,10.1 adapted to the shape of the non-resilient section of the gripper-finger, and with a thread 11 in which a clamping screw 12, passing diametrically through gripper-shaft, engages.
The clamping device formed with clamping piece 9,9.1 comprises means for adjusting the contact between the tip of the gripper and the gripper-pad, namely adjusting screw 13 which engages in a threaded hole 14 in clamping piece 9,9.1 and bears against the lower surface of spring-section 1.
In this case, the gripper-finger is preloaded by adjusting screw 13, so that if this screw and the gripper-pad were removed, spring-section 1 would arch downwardly in its relieved position and with the gripper-shaft in the position of rotation shown in Figs. 4 and 5.
~297S10 The examples of embodiment according to Figs. 4 and 5 differ as to the way in which the non-resilient section of the gripper~finger bears upon the gripper-shaft.
In the case of Fig. 4, the contour of the gripper-shaft in this area is circular, whereas in the case of Fig. 5 it has a flat, so thak the surface 10.1 of clamping piece 9.1 is also flat.
Figs. 6 and 7 show an example of embodiment in which the neutral fibres in spring section 1.3, 1.4 of the gripper finger according to the invention lie in plane 60 defined by the longitudinal axis of gripper-shaft 27, 28 and tip 29, 30 of the grippPr.
In this case, the gripper-finger consists of a top part 31, 32 , a bottom part 33, 34 and a spring-section joining these two parts which is in the form of two spring-rods 35, 36 and 37, 38 in parallel with, and spaced from, each other, bottom part 33, 34 being secured directly to the gripper-shaft. The lengths of the spring rods may be selected independently of each other. The example according to Fig. 6 may again be used with advantage wherever space is not a problem, whereas the example according to Fig. 7 is more suitable for close quarters. As already indicated, this has to do with the interaction bet~een admissible bending stress and deflection of the spring-rods.
For the purpose of securing bottom part 33, 34, this is adapted to the contour of the gripper shaft, to which it is screwed by means of retaining screws 39, 40.
The example according to Fig. 7 is an alternative to 1297~
that in Figs. 1 and 2 in which the cross-section of the gripper-shaft is not weakened by the diametral recess provided there, in spite of which a long resilient section of the gripper-finger may be selected. To this end, spring-rods 37, 38 are arranged sym~etrically with the gripper-shaft and held by retaining screws 40 engaging in blind threaded holes in the gripper-shaft.
In this case (Figs. 6, 7) the adjusting means consist of an abutment 41, 42 projecting from the bottom part and of adjusting screws 43, 44 resting thereupon and engaging in threads in the relevant top part. By means of these adjusting screws, the spring-section, in the form of parallel spring-rods 35, 36 - 37, 38 as described hereinbefore, are held under preload in a position parallel with plane 60.
As shown in Figs. 6 and 7, the top part, the bottom part, the abutment and the spring-rods may be in the form of a one-piece gripper-finger.
Fig. 8 shows a modification of the example according to Fig. 7 which is suitable for short runs. In this case spring-rods 45, 46 are made out of the legs of a U-shaped leaf-spring. The part of the leaf-spring uniting the two legs is screwed to top part 52. The ends of the legs are are clamped between gripper-shaft 27 and a clamping shell 48 adapted to the cross-section thereof which clamps the two leg-ends jointly. To this end, the said clamping shell surrounds about one half of the circumference of gripper;shaft 47. Arranged on the side of the ~Z9751t~
- 20 ~
gripper-shaft facing clamping shell 48, between the legs of the U-shaped leaf-spring, is an adjusting block 49. This is adapted to the contour of the gripper-shaft and is braced thereto, jointly with clamping piece 48, by means of a retaining screw 50 passing through the said gripper-shaft. Adjusting screws 51, engaging in threads in the adjusting block, are screwed down onto the upper leg of the leaf-spring. Adjusting block 49 and adjusting screws 51 form the adjusting means whereby spring-section 1.5 of gripper-finger 2.5 is held under preload in a position parallel with plane 60. The said adjusting screws are spaced from each in the longitudinal direction of the gripper-shaft. This makes it possible to twist the gripper-finger, if necessary, so that the tip of the gripper lies flatly upon the gripper pad.
Although the adjusting screws lose their effect as soon as the gripper-shaft, after the tip of the gripper has come into contact with the gripper-pad, is pivoted further in the direction of closing. However9 the snug fit between the tip of the gripper and the pad if the gripper-finger is made so that it can be twisted.
A further design modification in the examples according to Figs. 6 and 7 is the gripper-finger of so-called composite design. In this case, top part 31, 32 and bottom part 33, 34 are made, for example, of an aluminum alloy, while the spring-rods are made of spring-steel and are cast into the said top and bottom parts.
A gripper-device of this kind is known from EP-OS O 152 553. In this case the gripper-finger is made resilient and is screwed to a divided clamping piece which connects it to the gripper-shaft but secures it against rotation in relation thereto.
When this gripper-device closes, the tip of the gripper-finger initially comes into contact with a gripper-pad. In order to ensure an adequate retaining force in the a-rea, covered by the tip of the gripper, of a printed sheet, the gripper-shaft is rotated further in the direction of closing. In this case, the retaining force is the result of the deflection of the tip of the gripper, associated therewith, from its assumed position in relation to the clamping piece when the gripper-device is in the open condition.
As a result of the contact between the tip of the gripper and the gripper-pad, the circular motion of the tip of the gripper is ~Z975~0 interrupted. Further rotation of the gripper-shaft in the direction of closing causes the gripper-finger to behave like a connecting rod wh;ch is resilient in the direction of rotation of a crank-drive, is clamped firmly to the crankshaft, and is guided in a cross-head. As a result of this, the tip of the gripper moves in relation to the gripper-pad and thus interferes with the keeping of the register of a clamped printed sheet.
A gripper-device known from EP-PS 0 073 955 uses the analogy between a gripper-device of this kind and a crank-drive to restrict this displacement of the tip of the gripper to the shortest path. It makes use, to this end, of a bent, resilient gripper-finger, the resilient end of which, facing the gripper shaft, and the tip of which, lie upon a common straight line passing through the middle of the gripper-shaft. In this connection, a Z-shaped configuration of the gripper-finger causes the straight section thereof to behave approximately like the arms of a multiple articulated lever hinged to the gripper-shaft in the clamped position of the gripper-finger. As a result of changes in the angular position of the arms of the lever, restoring forces act upon these arms, and the end corresponding to the tip of the gripper bears frictionally upon the gripper-pad under the retaining force of the gripper-finger. The increase in the distance between the gripper-pad and the clamped end of the gripper finger, associated with rotation of the gripper-shaft by the stated amount in order to provide the said retaining force, is intended to produce, in this known device, upon deflection of the gripper-finger in its longitudinal direction, an automatic corresponding increase in the effective length of the gripper-finger. This is intended to prevent displacement of the tip of the gripper on the gripper-pad.
Actually, however, the desired effect is not achieved with the means disclosed. Instead, as a result of its Z-shaped design, the gripper-finger is very flexible in the direction passing through the middle of the gripper-shaft and through the tip of the gripper. As a result of this, the tip of the gripper shifts when the gripper closes or in the event of tensile forces from the paper. This effect cannot be eliminated with the known gripper without additional measures.
Another attempt to prevent the said displacement of the tip of the gripper on the gripper-pad is known from the device according to US Patent 2 906 204.
This is intermediate between a gripper-finger secured to the gripper-shaft and a gripper-part adapted to pivot about the gripper-shaft and acted upon by a closing spring, as may be gathered from US Patent 3 536 321.
The device according to US Patent 2 906 204 is intended to prevent the said displacement by means of a floating gripper-finger. The rear part of this engages around about half the circumference of the gripper-shaft, but does not bear upon it.
Only the areas thereof adjoining the semicircular part are caused to bear, under the force of a spring, against a half-shell connected to the gripper-shaft but secured against rotation in relation thereto. The area of the gripper-finger remote from the tip, bearing under spring-force against the lower half of the shell, is also held, by means of a bore in the gripper-finger at right angles to the supporting surface of the gripper-finger on the half-shell and a bolt alignment therewith, for the purpose of lZ~7S~O
clamping the lower and upper half-shells, in such a manner that the gripper-finger, after leaving the opposing supporting area, can tilt in relation to the bolt.
As a whole, this known device constitutes a so-called hook-gripper with which additional rotation of the gripper-shaft by the stated amount is to be used to obtain an adequate retaining force by resilient support of the gripper-finger. Here again - as in the case of the Z-shaped design - the gripper, when loaded in its longitudinal direction through the middle of the gripper-shaft and defined by the tip of the gripper, is not resistant to bending. Instead, the material carried around the gripper-shaft permits the gripper to deflect in the longitudinal direction and leads to displacement upon the paper.
Furthermore, floating mounting of the gripper-finger does not ensure reproducible grasping and holding of a printed ! sheet at one and the same location. Play-free mounting of the gripper-finger, however, is an important prerequisite in obtaining register-keeping pressure.
A gripper-finger, the spring-section of which consists of two spring-rods arranged in parallel with, and spaced from, each other, is known per se from US Patent 3,536,321.
In this case, however, a stack of springs is secured rigidly to a first ring adapted to rotate freely upon the gripper-shaft. In the one direction of rotation, this ring is carried along by a second ring secured to the gripper shaft while, in the other direction of rotation, it is rotated against a stop by the action of a tension-spring. Arranged at the top end of the gripper-finger is a guide-rod passing through a platform of the loose ring. Under the action of a compression-spring bearing against this platform, the said guide-rod urges the top end in the direction of closing. It is pressed in the opposite direction by the second ring connected to the gripper-shaft but secured against rotation in relation thereto.
Moreoever, the arrangement as a whole is such that the spring-rods are substantially relieved upon contact with the gripper-pad, and the retaining force is applied by the compression spring clamped between the end of the guide-rod and the platform.
The spring-rods thus assume the function of approximately parallel guidance of the tip of the gripper in the end-phase of the closing movement.
For the purpose of adjusting the contact between the tip of the gripper and the gripper-pad, a foot adjustable along the guide-rod is provided, against which the other end of the compression-spring, one end of which bears against the said platform, bears.
This gripper-device naturally has a certain amount of play in the mounting of the gripper-finger on the gripper-shaft.
The mass-inertia forces are varied during rotation in each direction by tightening or loosening the loose ring of the driver.
Co-operation with the springs activated thereby also causes unwanted torsional vibration in the gripper-device as a whole. It is the purpose of the present invention to design a gripper-device of the type mentioned at the beginning hereof in such a manner ~Z9751~
that, even with the simplest possible design of gripper-finger, displacement of the tip of the gripper on the gripper-pad is almost zero.
According to the invention, this purpose is accomplished, with a gripper-device of the type mentioned at the beginning hereof, in that the neutral fibres of the spring-section adjoining the tip of the gripper, when designed as an individual spring-rod, run substantially in the plane defined by the longitudinal axis of the gripper-shaft and by the tip of the gripper, and when designed in the form of spring-rods arranged in parallel with, and spaced from, each other, run in planes parallel with this plane.
The object of the invention opens up the possibility, especially when using only one spring-rod, of providing a device with a relatively small mass moment of inertia which may be used with advantage in high-speed printing machines.
The configurations of the object of the invention may be easily assembled and disassembled, with no need to remove the gripper-shaft from the machine.
Furthermore, the adjusting means provide accurate individual adjustment of the contact between the tip of the gripper and the printed sheet clamped between it and the gripper-pad, so that production tolerances and, if so desired, differences in the thickness of the paper may easily be compensated for.
In contrast to the floating gripper-finger known from ~Z97~
the cited state of the art, the object of the invention ensures reproducible placement of the tip of the gripper upon a spPcific contact location in relation to the printed sheet, so that the latter is not subjec~ed to changes arising from differences in gripper action.
All of this requires only a relatively small number of very simple and light components, so that precise functioning may abe acnieved inexpensively.
The object of the invention is particularly suitable for incorporation into a printing machine in such a manner that the middle of the gripper-shaft is located externally of the imaginary extension of the sheet material clamped by the gripper-device beyond the front edge thereof.
Special shaping of the gripper-finger, in order to achieve a preload in the installed position, may be dispensed with.
One advantageous configuration of the object of the invention is characterized in that a gripper-finger having a spring-section in the form of a single spring-rod, passes freely through the gripper-shaft, the end thereof remote from the tip of the gripper being clamped to provide a rigid connection to the gripper-shaft.
A gripper-device of this kind may be used with advantage in close quarters, since it permits the use of relatively long and therefore flexible gripper-fingers at short distances between the gripper-shaft and the gripper-pad, thus preventing any ~ 8 -inadmissible bending stresses.
According to another configuration, in the vicinity of the opening remote from the tip of the gripper in a diametral recess through which the gripper-finger passes, the cross-sections of the recess and of the spring-rod match each other over a short length.
This facilitates alignment of the gripper-finger with the gripper-shaft.
According to another configuration, a clamping dev;ce, which connects the gripper-finger rigidly to the gripper-shaft, comprises a cylindrical clamping sleeve clamped between two jaws braced to the gripper-shaft and provided with a central longitudinal slot in which the spring-rod is clamped.
As a result of this, the gripper-finger is rotatable along with its longitudinal axis and may thus be aligned, particularly simple, to bear snugly upon a gripper-pad associated therewith, for which purpose the clamping device need only be loosened slightly.
Another configuration is characterized in that the end of the spring-rod remote from the tip of the gripper comprises a cylindrical extension integral with the spring-rod, the longitudinal axis of the said extension being in alignment with the longitudinal axis of the diametral recess and the said extension being clamped between the jaws braced to the gripper-shaft.
This facilitates still further the assembly of the gripper-device.
According to another configuration, a second section of the spring-rod, adapted to the external contour of the gripper-shaft adjoins the spring-section of the gripper-finger designed as a spring-rod, the said second section bearing upon the gripper-shaft and being clamped between it and a clamping piece comprising adjusting means.
A gripper-device of this kind may be used with advantage whenever space is not a problem.
Another configuration is characterized by a compression-spring arranged in parallel with a gripper-finger designed as a spring-rod, the direction in which fDrce is introduced being at right angles to the neutral fibres, the said compression-spring bearing upon a clamping device comprising adjusting means for connecting the gripper-finger to the gripper-shaft.
This provides particularly satisfactory conditions as regards bending stress when the gripper-finger is in the clamped position.
According to another configuration, gripper-fingers, in which the neutral fibres of the spring-section run in planes parallel with the plane determined by the longitudinal axis of the gripper-shaft and by the tip of the gripper, are formed by a bottom part and a top part, with the spring section connecting the bottom part in the form of two parallel rods are secured with the bottom part directly to the gripper-shaft.
This facilitates assembly still further.
According to another configuration the spring-rods are arranged symmetrically with the gripper-shaft.
~2g7510 This configuration combines the advantage of simplified assembly and the applicability of a gripper-device according to the invention to close quarters, since this means that the spring-rods may be extended beyond the middle of the gripper-shaft.
Another configuration is characterized in that one of the parts of the gripper-finger, connected together by the spring-rods, comprises an abutment of the adjusting means, while the other part comprises an element of the adjusting means bearing upon the said abutment.
According to another configuration, the top part, the bottom part, the abutment and the spring-rods form a one-piece gripper-finger.
In this case the gripper-finger may be produced highly economically from an extruded section.
Another configuration is characterized in that the two spring-rods are formed by the legs of a U-shaped leaf-spring, in that the part of the leaf-spring uniting the two legs is clamped to the non-resilient top part, and in that the ends of the legs are clamped between the gripper-shaft and a clamping shell adapted to the cross-section thereof.
A gripper-device of this kind is particularly suitable for short runs.
According to another configuration, a common clamping shell is provided for both leg-ends.
In the case of a gripper-device particularly suitable ~Zg751~
for short runs, this reduces the number of necessary parts.
Another configuration is characterized in that arranged on the side of the gripper-shaft facing the clamp;ng shell, between the legs of the U-shaped leaf--spring, is an adjusting block adapted to the contour of the gripper-shaft, the said block being clamped to the gripper-shaft jointly with the clamping shell and compris;ng adjusting means adapted to be applied to the upper leg of the leaf-spring.
This provides good accessibility to the attachment means for a gripper-device consisting of a plurality of individual parts.
According to another configuration, the adjusting means provided are such that they may be used to lock the gripper-finger.
Another configuration is characterized in that adjusting means designed to twist the gripper-finger comprise two adjusting screws spaced apart in the longitudinal direction of the gripper-shaft.
Gripper-devices designed according to another configuration make it possible for the gripper-finger, without loosening the clamping means with which it is secured to the gripper shaft, to be set up in such a manner that the tip of the gripper rests flatly upon the gripper-pad associated therewith.
According to another configuration, the gripper finger is of composite design.
This provides for optimal adaptation of the choice of materials to given requirements for the different sections of a gripper-finger according to the invention, for example satisfactory adhesion of the surface of the tip of the gripper and sat;sfactory resiliency of the spring-section of the gripper-finger.
According to another configuration, the components constituting the spring-section are preferably made of a fibre-reinforced synthetic material.
This makes it possible to reduce still further the mass moment of inertia of a gripper-finger according to the invention.
Examples of embodiment and advantageous configurations of the invention are explained hereinafter in greater detail in conjunction with the drawings attached hereto, wherein:
Fig. 1 is a cross section through a gripper-shaft carrying a gripper-finger in the form of a spring rod for an example in which the gripper-finger passes through the gripper-shaft;
Fig. 2 is a cross-section along the line 2 in Fig. l;
Fig. 3 is a corresponding part-section of an example with a gripper-finger rotatable in its clamped position;
Fig. 4 is a corresponding cross-section of an example with a gripper-finger bearing against the gripper-shaft in the form of a spring-rod;
~2g7510 F;g. 5 ;s a correspond;ng cross-section of an example in which the bearing of the gripper-finger upon the gripper-shaft is modified:
Fig. 6 is a cross-section through a gripper-shaft w;th S a gripper-finger consisting of parallel spring-rods mounted thereupon;
Fig. 7 is a corresponding cross-section of an exampl e w;th spr;ng-rods arranged symmetrically with the gripper-shaft, Fig. 8 is a corresponding cross-section through an alternative to Fig. 7, Fig. 9 is a plan view of a gripper device according to F;g. 8.
Figs. 1 and 2 ;llustrate an example of embodiment which is particularly suitable for use in close quarters. In this case, gripper-shaft 15 is provided with a diametral recess 16 the cross-sect;on of which is larger than that of the gripper-f;nger passing through the said recess.
The gripper-finger is in the form of a spring-rod which carries at one end a gripper-tip 3 and is clamped at the other end, externally of opening 21, remote from the tip of the gripper, in recess 16, between two jaws 17, 18 which, in turn, are braced to gripper-shaft 15 by means of two screws 19, 20.
Jaws 17, 18 therefore constitute the rigid connection between gripper-finger 2.2 and gripper-shaft 15.
lZ975~() - 14 ~
The lower jaw (in Fig. 1) also comprises adjusting means in the form of a screw 13 which engages in a threaded hole 14 in the lower jaw and bears against the gripper-finger.
Arranged between the upper surface of gripper-finger 2~2 and upper jaw 17 is a compression-spring 23 which bears upon the spring-rod. The direction of the force of this spring is at right angles to the neutral fibres of resilient section 1.2.
Fig. 1 illustrates the operative condition in which the tip of the gripper comes into contact with gripper-pad 8. In this case, the neutral fibres of the spring-rod lie in plane 60 defined by the longitudinal axis of the gripper-shaft and by the gripper tip. In this position, the gripper-finger is already preloaded by the compression spring and its own preload. These preloads are picked up by adjusting screw 14. In order to achieve an adequate retaining force of the tip of the gripper upon the pad, it therefore needs only an extremely slight deflection of the tip of the gripper in relation to the clamped other end of the spring-rod since, as soon as the spring-rod is lifted off adjusting screw 14, the preload forces act upon the gripper-pad as a result of additional pivoting of the gripper-shaft in the direction of closing.
In order to facilitate rapid and positionally correct assembly of the gripper-device to the gripper-shaft, in the vicinity of mouth 21, remote from the tip of the gripper, of diametral recess 16, the cross-sections of recess 16 and gripper-finger 2.2 match each other over a short length (Fig.2).
1297~1~
In the configuration according to Fig. 3, the end of the spring-rod remote from the tip of the gripper is accomodated in a central slot between upper and lower jaws 17.1, 1~.1 of a clamped sleeve 24. To this end thP said jaws are shaped in such a manner that the left-hand ends thereof (Fig.3) form a cylindrical pick up 25 for similarly cylindrical sleeve 24. Thus by rotating the clamping sleeve and then bracing the two jaws, the spring-rod may be adjusted in such a manner that the tip of the gripper bears uniformly upon the gripper-pad. The said sleeve is provided with flats so that it can be rotated by means of a tool.
According to a configuration not shown in the drawing, spring-rod 2.2 and clamping sleeve 24 (Fig. 3) may also be made in one piece. To this end, the end of the spring-rod remote from the tip of the gripper is provided with a cylindrical extension which fits rotatably in pick-up 25.
In this connection, rapid and positionally correct assembly is achieved in that the diameters of the diametral recess and of the cylindrical extension are adapted to each other, the pick-up, formed with the clamping jaws, for the cylindrical extension, is in alignment with the diametral recess, and the cylindrical extension engages, over a short length, in the said diametral recess.
In order to rotate the cylindrical extension~ and thus the tip of the gripper also, into a position in which the latter lies uniformly upon the gripper-pad, it is again desirable to provide the cylindrical extension with flats for a tool.
Figs. 4 and 5 show gripper-devices according to the invention which m~y be used with advantage in a sheet-transferring lZ9751~) - 16 ~
device or the impression-cylinder of a printing machine. If sufficient room is available, resilient section 1 of gripper-finger 2.2.1 may be made so long that major deflections of tip 3 of the gripper, during the processing cardboard, for example, do not produce inadmissibly high bending stresses at clamping location 4.
The neutral fibres of the spring section of the gripper-finger lie in a position preloaded by the adjusting means in plane ~0 which is defined by the longitudinal axis of gripper-shaft 5,5.1 and tip 3 of the gripper.
Gripper-finger 2,2.1 is in the form of a spring-rod carrying tip 3 at its free end. The gripper-devices (Figs. 4,5) are again shown in the operative condition in which the tip of the gripper is just coming into contact with the gripper-pad. In the examples of embodiment shown, this is a pad 8 secured to a wall 6 of a channel in a cylinder 7.
For the purpose of actuating the gripper-device, gripper-shaft 5 is rotated, in known fashion, through a specific angle in relation to cylinder 7 in one direction and the other.
By corresponding clockwise rotation through a first part of the pivot-angle, the tip of the gripper moves from a position, not shown, corresponding to the open gripper-device, into the position shown in the drawing. Further rotation through the remaining part of the angle presses the tip of the gripper against pad 8 and applies a retaining force, the printed sheet being thus clamped between the tip of the gripper and the gripper-pad.
1Z~7510 - 17 _ At the same time, deflection of the spring section deflects tip 3 of the gripper to a small extent in relation to clamping location 4 in the direction of an arc around the said clamping location.
All that is necessary to produce an adequate retaining force is again a very slight deflection of the tip of the gripper, since the gripper-finger is already preloaded by the adjusting means. In this connection there is practically no displacement of the tip of the gripper on the gripper-pad as a result of this deflection.
Gripper-finger 2,2.1, in the form of a spring-rod (Figs.
4,5), comprises a non-resilient section adjoining spring-section 1, and is clamped between it and the clamping piece. To this end, the said clamping piece is provided with a supporting surface 10,10.1 adapted to the shape of the non-resilient section of the gripper-finger, and with a thread 11 in which a clamping screw 12, passing diametrically through gripper-shaft, engages.
The clamping device formed with clamping piece 9,9.1 comprises means for adjusting the contact between the tip of the gripper and the gripper-pad, namely adjusting screw 13 which engages in a threaded hole 14 in clamping piece 9,9.1 and bears against the lower surface of spring-section 1.
In this case, the gripper-finger is preloaded by adjusting screw 13, so that if this screw and the gripper-pad were removed, spring-section 1 would arch downwardly in its relieved position and with the gripper-shaft in the position of rotation shown in Figs. 4 and 5.
~297S10 The examples of embodiment according to Figs. 4 and 5 differ as to the way in which the non-resilient section of the gripper~finger bears upon the gripper-shaft.
In the case of Fig. 4, the contour of the gripper-shaft in this area is circular, whereas in the case of Fig. 5 it has a flat, so thak the surface 10.1 of clamping piece 9.1 is also flat.
Figs. 6 and 7 show an example of embodiment in which the neutral fibres in spring section 1.3, 1.4 of the gripper finger according to the invention lie in plane 60 defined by the longitudinal axis of gripper-shaft 27, 28 and tip 29, 30 of the grippPr.
In this case, the gripper-finger consists of a top part 31, 32 , a bottom part 33, 34 and a spring-section joining these two parts which is in the form of two spring-rods 35, 36 and 37, 38 in parallel with, and spaced from, each other, bottom part 33, 34 being secured directly to the gripper-shaft. The lengths of the spring rods may be selected independently of each other. The example according to Fig. 6 may again be used with advantage wherever space is not a problem, whereas the example according to Fig. 7 is more suitable for close quarters. As already indicated, this has to do with the interaction bet~een admissible bending stress and deflection of the spring-rods.
For the purpose of securing bottom part 33, 34, this is adapted to the contour of the gripper shaft, to which it is screwed by means of retaining screws 39, 40.
The example according to Fig. 7 is an alternative to 1297~
that in Figs. 1 and 2 in which the cross-section of the gripper-shaft is not weakened by the diametral recess provided there, in spite of which a long resilient section of the gripper-finger may be selected. To this end, spring-rods 37, 38 are arranged sym~etrically with the gripper-shaft and held by retaining screws 40 engaging in blind threaded holes in the gripper-shaft.
In this case (Figs. 6, 7) the adjusting means consist of an abutment 41, 42 projecting from the bottom part and of adjusting screws 43, 44 resting thereupon and engaging in threads in the relevant top part. By means of these adjusting screws, the spring-section, in the form of parallel spring-rods 35, 36 - 37, 38 as described hereinbefore, are held under preload in a position parallel with plane 60.
As shown in Figs. 6 and 7, the top part, the bottom part, the abutment and the spring-rods may be in the form of a one-piece gripper-finger.
Fig. 8 shows a modification of the example according to Fig. 7 which is suitable for short runs. In this case spring-rods 45, 46 are made out of the legs of a U-shaped leaf-spring. The part of the leaf-spring uniting the two legs is screwed to top part 52. The ends of the legs are are clamped between gripper-shaft 27 and a clamping shell 48 adapted to the cross-section thereof which clamps the two leg-ends jointly. To this end, the said clamping shell surrounds about one half of the circumference of gripper;shaft 47. Arranged on the side of the ~Z9751t~
- 20 ~
gripper-shaft facing clamping shell 48, between the legs of the U-shaped leaf-spring, is an adjusting block 49. This is adapted to the contour of the gripper-shaft and is braced thereto, jointly with clamping piece 48, by means of a retaining screw 50 passing through the said gripper-shaft. Adjusting screws 51, engaging in threads in the adjusting block, are screwed down onto the upper leg of the leaf-spring. Adjusting block 49 and adjusting screws 51 form the adjusting means whereby spring-section 1.5 of gripper-finger 2.5 is held under preload in a position parallel with plane 60. The said adjusting screws are spaced from each in the longitudinal direction of the gripper-shaft. This makes it possible to twist the gripper-finger, if necessary, so that the tip of the gripper lies flatly upon the gripper pad.
Although the adjusting screws lose their effect as soon as the gripper-shaft, after the tip of the gripper has come into contact with the gripper-pad, is pivoted further in the direction of closing. However9 the snug fit between the tip of the gripper and the pad if the gripper-finger is made so that it can be twisted.
A further design modification in the examples according to Figs. 6 and 7 is the gripper-finger of so-called composite design. In this case, top part 31, 32 and bottom part 33, 34 are made, for example, of an aluminum alloy, while the spring-rods are made of spring-steel and are cast into the said top and bottom parts.
Claims (23)
1. Gripper device for a printing machine for handling sheet-shaped material with a gripper support a gripper shaft swivellable about its longitudinal axis and a gripper finger firmly connected to the gripper shaft so that the gripper point thereof is movable away from a gripper support when the gripper shaft is swivelled in a first direction, is initially displaceable into contact with the gripper support when the gripper shaft is swivelled in a second direction opposite to the first direction, and is capable of exerting a holding force on the gripper support when the gripper shaft is swivelled farther in the second direction, and means for adjusting contact between the gripper point and the gripper support, comprising a resilient section forming a part of the gripper finger and connected to the gripper point, said resilient section having neutral fibers and formed as at least one resilient rod extending substantially in the direction of a plane determined by the longitudinal axis of the gripper shaft and by the gripper point.
2. Gripper device according to claim 1, wherein said resilient section is formed as a single resilient rod extending substantially in said plane determined by the longitudinal axis of the gripper shaft and by the gripper point.
3. Gripper device according to claim 1, wherein said resilient section is formed of two mutually resilient rods spaced from one another, connected in parallel with one another and extending in planes parallel to said first-mentioned plane.
4. Gripper device according to claim 1, including a clamping member having the contact adjusting means, and wherein a second section of said resilient rod matching the outer contour of the gripper shaft is connected to said resilient section of said gripper finger, said second section being in engagement with the gripper shaft and being clamped between the gripper shaft and the clamping member having the adjusting means.
5. Gripper device according to claim 1 including a clamping member having the contact adjusting means, and a compression spring having a force-applying direction substantially perpendicular to the neutral fibers, said compression spring having a spring force acting in parallel with a corresponding force of the gripper finger formed as a resilient rod, said compression spring being braced against the clamping member having the adjusting means for connecting the gripper finger to the gripper shaft.
6. Gripper device according to claim 1, wherein the adjusting means is constructed so as to twist the gripper finger.
7. Gripper device according to claim 1, the adjusting means having setscrews spaced in longitudinal direction of the gripper shaft, said setscrews being adjustable for twisting the gripper finger.
8. Gripper device according to claim 1, wherein components of said resilient section are formed of fiber-reinforced plastic material.
9. Gripper device for a printing machine for handling sheet-shaped material with a gripper support, a gripper shaft swivellable about its longitudinal axis and a gripper finger firmly connected to the gripper shaft, said gripper finger being formed with a gripper point which is movable away from the gripper support when the gripper shaft is swivelled in a first direction, is initially displaceable into contact with the gripper support when the gripper shaft is swivelled in a second direction opposite to the first direction, and is capable of exerting a holding force on the gripper support when the gripper shaft is swivelled farther in the second direction, and means for adjusting contact between the gripper point and the gripper support, comprising a resilient section forming a part of the gripper finger and connected to the gripper point, said resilient section having neutral fibers and being formed as a single resilient rod extending substantially in a plane determined by the longitudinal axis of the gripper shaft and by the gripper point, said resilient section extending freely through the gripper shaft and being firmly clamped, at the end thereof facing away from the gripper point, to the gripper shaft.
10. Gripper device according to claim 9, wherein the gripper shaft is formed with a recess through which the gripper finger extends diametrically, said recess having an opening facing away from the gripper point, said recess and said resilient rod having a cross section matching one another over a short length in vicinity of said opening.
11. Gripper device according to claim 10, wherein a clamping device connecting the gripper finger firmly with the gripper shaft has a cylindrical clamping sleeve formed with a central slot and clamped between two clamping jaws braced with the gripper shaft, the resilient rod being clamped in said slot formed in said clamping sleeve.
12. Gripper device according to claim 11, wherein said resilient rod, at the end thereof facing away from the gripper point, has a cylindrical extension formed integrally with the resilient rod and having a longitudinal axis aligned with the longitudinal axis of the diametric recess, said cylindrical extension being clamped between the clamping jaws braced with the gripper shaft.
13. Gripper device for a printing machine for handling sheet-shaped material with a gripper support, with a gripper shaft swivellable about its longitudinal axis and a gripper finger firmly connected to the gripper shaft, said gripper shaft being formed with a gripper point which is movable away from the gripper support when the gripper shaft is swivelled in a first direction, is initially displaceable into contact with the gripper support when the gripper shaft is swivelled in a second direction opposite to the first direction, and is capable of exerting a holding force on the gripper support when the gripper shaft is swivelled farther in the second direction, and means for adjusting contact between the gripper point and the gripper support, comprising a resilient section forming a part of the gripper finger and connected to the gripper point, said resilient section having neutral fibers and being formed of two mutually resilient rods spaced from and connected in parallel with one another, said resilient rods extending in planes parallel to a plane passing through the longitudinal axis of the gripper shaft and through the gripper point, the gripper finger being formed of a head portion carrying the gripper point, a foot portion and a resilient section connecting the head portion to the foot portion and formed of said parallel resilient rods, and being connected by the foot portion directly with the gripper shaft so as to be secured against torsion.
14. Gripper device according to claim 13, wherein said resilient rods are arranged symmetrically to the gripper shaft.
15. Gripper device according to claim 13, wherein one of the parts of the gripper finger mutually connected by said resilient rods has a counterbearing of the adjusting means, and the other of the parts has an adjusting member of the adjusting means braced against said counterbearing.
16. Gripper device according to claim 15, wherein said head portion, said foot portion, said counterbearing and said resilient rods form an integral gripper finger.
17. Gripper device according to claim 14, including a clamping shell matching the cross section of the gripper shaft, and wherein the head portion of the gripper finger is non-resilient, and both of said resilient rods are formed of legs of a U-shaped angularly bent leaf spring, said leaf spring having a part mutually connected said legs thereof and clamped to said non-resilient head portion of the gripper finger, said legs having ends which are clamped between the gripper shaft and the clamping shell.
18. Gripper device according to claim 17, wherein a common clamping shell is provided for both the ends of said legs.
19. Gripper device according to claim 17, including an adjusting block arranged on the side of the gripper shaft located opposite said clamping shell and between said legs of said U-shaped leaf spring, said adjusting block matching the contour of the gripper shaft and being clamped together with said clamping shell against the gripper shaft, said adjusting block carrying setting means engageable with one of the legs of said leaf spring.
20. Gripper device according to claim 13, wherein the gripper finger has a compound construction.
21. Gripping device for the handling of sheet-shaped items in a printing machine, with a gripping spindle which can be swivelled about its longitudinal axis, and with a gripping finger fitted with a spring section, which is rigidly connected with the gripping spindle such that a gripper point of the gripping device is moved away from a gripper support when the gripping spindle is swivelled in a first direction, and when swivelled in the opposite second direction, said gripper point first touches the gripper support, and when further swivelled in the second direction exerts a stopping force on the gripper support; said gripping device including means for adjusting the contact between the gripper point of the gripping device and the gripper support; said means for adjusting including said spring section with the center of gravity lines running in the spring section up to the point of contact of the gripper point of the gripping device with the gripper support, between and essentially parallel to planes parallel to each other, which in turn are parallel to a plane determined by the longitudinal axis of the gripping spindle and by the gripper point of the gripping device.
22. Gripping device according to claim 21, wherein the spring section consists of a single spring bar.
23. Gripping device according to claim 21, wherein the spring section consists of two spaced spring bars.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3644484.7 | 1986-12-24 | ||
| DE19863644484 DE3644484A1 (en) | 1986-12-24 | 1986-12-24 | GRIPPER DEVICE FOR A PRINTING MACHINE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1297510C true CA1297510C (en) | 1992-03-17 |
Family
ID=6317231
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000553029A Expired - Lifetime CA1297510C (en) | 1986-12-24 | 1987-11-27 | Gripper-device for a printing machine |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4846061A (en) |
| EP (1) | EP0272469B1 (en) |
| JP (1) | JP2628873B2 (en) |
| CN (1) | CN1005546B (en) |
| AU (1) | AU599440B2 (en) |
| CA (1) | CA1297510C (en) |
| DE (2) | DE3644484A1 (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3921474A1 (en) * | 1989-06-30 | 1991-01-10 | Heidelberger Druckmasch Ag | ARCH GRIPPER DEVICE FOR ARC ROTATION PRINTING MACHINES |
| DE4101987A1 (en) * | 1991-01-24 | 1992-07-30 | Roland Man Druckmasch | Sheet gripper for rotary printing machine - has self-aligning claw attached by leaf spring to gripper finger |
| DE4127713C2 (en) * | 1991-08-22 | 1996-03-21 | Koenig & Bauer Albert Ag | Grippers for sheet-fed rotary printing machines |
| US5201516A (en) * | 1992-05-07 | 1993-04-13 | Xerox Corporation | Sheet gripping apparatus |
| DE4315844C2 (en) * | 1992-07-22 | 1999-12-02 | Heidelberger Druckmasch Ag | Sheet gripper on a paper-guiding cylinder of a sheet-fed printing machine |
| DE4317429C2 (en) * | 1993-05-26 | 2001-06-13 | Heidelberger Druckmasch Ag | Device for non-rotatably adjustable fastening of a gripper stop in the phase angle |
| DE4434151C2 (en) * | 1994-09-24 | 2000-05-25 | Heidelberger Druckmasch Ag | Grippers for sheet-fed printing machines |
| JPH08183166A (en) * | 1994-12-28 | 1996-07-16 | Riso Kagaku Corp | Printing paper start end fitting device for rotary screen process printer |
| DE19804039A1 (en) * | 1998-02-03 | 1999-08-05 | Heidelberger Druckmasch Ag | Suction gripper for transferring the rear edge of a sheet in a turning device of a sheet-fed rotary printing machine |
| EP0970808B1 (en) * | 1998-07-06 | 2003-09-10 | Heidelberger Druckmaschinen Aktiengesellschaft | Gripper for a sheet transfer cylinder or drum of a rotary printing machine |
| DE102007005958B4 (en) * | 2006-02-20 | 2015-07-16 | Heidelberger Druckmaschinen Ag | Device for sheet transport |
| CN101024328B (en) * | 2006-02-20 | 2010-12-15 | 海德堡印刷机械股份公司 | Sheet-transporting apparatus |
| DE102008043754A1 (en) | 2008-11-14 | 2010-05-20 | Steinemann Technology Ag | Sheet guiding system for sheet manufacturing printing, refinement or processing machine, has grippers for guiding sheets, where sheet or finished printing product is gripped laterally to front or rear edge |
| DE102011085563B4 (en) | 2011-11-02 | 2022-01-20 | manroland sheetfed GmbH | Sheet processing machine with a gripper device |
| CN105966058A (en) * | 2016-07-07 | 2016-09-28 | 天津长荣印刷设备股份有限公司 | Positioning micro-adjusting device applicable to unit type die cutting and hot foil stamping machine and working method thereof |
| CN106183394A (en) * | 2016-07-07 | 2016-12-07 | 天津长荣印刷设备股份有限公司 | The accurate-location device of a kind of set type die-cutting machine and method of work thereof |
| CN109941510B (en) * | 2019-03-26 | 2021-06-15 | 潍坊学院 | Automatic packaging method for roll paper in feeding mode from bottom to top |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2418065A (en) * | 1940-10-16 | 1947-03-25 | Bobst Henri | Blank feeding means |
| US2865289A (en) * | 1956-10-03 | 1958-12-23 | Dick Co Ab | Gripper construction for duplicators |
| US2906204A (en) * | 1957-06-24 | 1959-09-29 | Cottrell Company | Gripper assemblies |
| DE1900057B2 (en) * | 1968-01-03 | 1973-03-01 | Adamovske Strojirny, N.P., Adamov (Tschechoslowakei) | GRIPPER DEVICE OF A CHAIN BOOM OF A SHEET PRINTING MACHINE |
| US3536321A (en) * | 1968-06-13 | 1970-10-27 | Planeta Veb Druckmasch Werke | Device for clamping sheet material |
| US4058307A (en) * | 1975-11-03 | 1977-11-15 | American Screen Printing Equipment Company | Feed and takeoff assembly |
| DE2606347A1 (en) * | 1976-02-18 | 1977-08-25 | Maschf Augsburg Nuernberg Ag | FLEXIBLE GRIPPER CARRIAGE, IN PARTICULAR FOR OFFSET PRINTING MACHINES, AND METHODS FOR MANUFACTURING FLEXIBLE GRIPPER CARRIAGE STRUCTURES |
| US4203363A (en) * | 1976-03-22 | 1980-05-20 | Polygraph Leipzig Kombinat fuer Polygraphiscje Maschinen und Ausrustungen | Sheet gripper for printing cylinder and the like |
| DD145900A1 (en) * | 1979-10-25 | 1981-01-14 | Peter Kahlert | ARCH OVERALL DEVICE |
| EP0073955B1 (en) * | 1981-09-04 | 1985-11-13 | Motter Printing Press Co. | Gripper for sheet handling equipment |
| DD211760A1 (en) * | 1982-12-01 | 1984-07-25 | Hans Zimmermann | GRIPPING CARTS IN EQUIPMENT OF ARC PRINTING MACHINES |
| US4579331A (en) * | 1983-01-10 | 1986-04-01 | Veb Textil- Und Konfektionsbetrieb | Method and apparatus for gripping and separating sheets |
| DE8404981U1 (en) * | 1984-02-18 | 1984-05-10 | M.A.N.- Roland Druckmaschinen AG, 6050 Offenbach | BOW GRIPPERS FOR PRINTING MACHINES |
| DE3529639A1 (en) * | 1985-08-19 | 1987-02-26 | Roland Man Druckmasch | SPRING GRIPPER FOR ARC ROTATION PRINTING MACHINES |
| DE3529596A1 (en) * | 1985-08-19 | 1987-02-26 | Roland Man Druckmasch | SPRING GRIPPER FOR ARC ROTATION PRINTING MACHINES |
-
1986
- 1986-12-24 DE DE19863644484 patent/DE3644484A1/en active Granted
-
1987
- 1987-11-24 EP EP87117258A patent/EP0272469B1/en not_active Expired - Lifetime
- 1987-11-24 DE DE8787117258T patent/DE3769949D1/en not_active Expired - Lifetime
- 1987-11-27 CA CA000553029A patent/CA1297510C/en not_active Expired - Lifetime
- 1987-12-01 AU AU81960/87A patent/AU599440B2/en not_active Ceased
- 1987-12-21 CN CN87101186.7A patent/CN1005546B/en not_active Expired
- 1987-12-24 US US07/138,508 patent/US4846061A/en not_active Expired - Lifetime
- 1987-12-24 JP JP62325617A patent/JP2628873B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0272469A3 (en) | 1989-01-04 |
| US4846061A (en) | 1989-07-11 |
| CN1005546B (en) | 1989-10-25 |
| AU599440B2 (en) | 1990-07-19 |
| EP0272469B1 (en) | 1991-05-08 |
| AU8196087A (en) | 1988-06-30 |
| EP0272469A2 (en) | 1988-06-29 |
| JPS63168355A (en) | 1988-07-12 |
| DE3644484A1 (en) | 1988-07-07 |
| DE3644484C2 (en) | 1989-07-27 |
| CN87101186A (en) | 1988-07-06 |
| DE3769949D1 (en) | 1991-06-13 |
| JP2628873B2 (en) | 1997-07-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |